1. Field of the Invention
The present invention relates to a switching power supply.
2. Description of the Related Art
Japanese Patent Application Laid-open No. 2008-301581 discloses a switching type DC-DC converter having a soft-start circuit as a conventional switching power supply, for example. This soft-start circuit, until an output voltage of the converter reaches a set voltage, compares a voltage by a capacitor for soft start and a dividing resistor for soft start with a reference voltage that is equal to a voltage by a dividing resistor for output voltage detection when the output voltage is the set voltage, and controls a duty period of an output transistor.
Although the switching type DC-DC converter having the soft-start circuit reduces an overshoot of the output voltage at startup by being configured as described above, a more precise overshoot reduction is demanded, for example.